If a central bank creates a cryptocurrency which has unlimited coin supply, there will be no difference from today's monetary system and reserve paper money. So it's a pure centralized system.
But if they create a coin that limited supply like bitcoin, then we'd talk about partial or "semi" centralization. This coin would neutralize monetary policies and has an aspect of freedom.
We'll see what's going to happen in near future.
The point of state central bank stablecoins is not to create a stablecoin that looks like a cryptocurrency. The government wants to replace non-cash payments with its national currency with the same ones, but using blockchain technology. Therefore, their stablecoin will definitely be tightly centralized with unlimited stablecoin issuance. Due to the coronavirus pandemic, some of the cash will be replaced by the national stablecoin. The Chinese digitalized yuan will be launching soon, and we will take a closer look at such stablecoins in practice.
